POSIX_TRACE_GET_FILTER(P)				     POSIX Programmer's Manual					 POSIX_TRACE_GET_FILTER(P)

NAME

       posix_trace_get_filter, posix_trace_set_filter - retrieve and set the filter of an initialized trace stream (TRACING)

SYNOPSIS

       #include <trace.h>

       int posix_trace_get_filter(trace_id_t trid, trace_event_set_t *set);
       int posix_trace_set_filter(trace_id_t trid,
	      const trace_event_set_t *set, int how);

DESCRIPTION

       The  posix_trace_get_filter()  function	shall  retrieve, into the argument pointed to by set, the actual trace event filter from the trace
       stream specified by trid.

       The posix_trace_set_filter() function shall change the set of filtered trace event types after a trace stream identified by the trid  argu-
       ment  is  created.  This  function may be called prior to starting the trace stream, or while the trace stream is active. By default, if no
       call is made to posix_trace_set_filter(), all trace events shall be recorded (that is, none of the trace event types are filtered out).

       If this function is called while the trace is in progress, a special system trace event, POSIX_TRACE_FILTER, shall be recorded in the trace
       indicating  both  the old and the new sets of filtered trace event types (see Trace and Trace Event Filter Options: System Trace Events and
       Trace, Trace Log, and Trace Event Filter Options: System Trace Events ).

       If the posix_trace_set_filter() function is interrupted by a signal, an error shall be returned and the filter shall  not  be  changed.	In
       this case, the state of the trace stream shall not be changed.

       The value of the argument how indicates the manner in which the set is to be changed and shall have one of the following values, as defined
       in the <trace.h> header:

       POSIX_TRACE_SET_EVENTSET

	      The resulting set of trace event types to be filtered shall be the trace event type set pointed to by the argument set.

       POSIX_TRACE_ADD_EVENTSET

	      The resulting set of trace event types to be filtered shall be the union of the current set and the trace event type set pointed	to
	      by the argument set.

       POSIX_TRACE_SUB_EVENTSET

	      The  resulting  set  of  trace  event types to be filtered shall be all trace event types in the current set that are not in the set
	      pointed to by the argument set; that is, remove each element of the specified set from the current filter.

RETURN VALUE

       Upon successful completion, these functions shall return a value of zero. Otherwise, they shall return the corresponding error number.

       The posix_trace_get_filter() function stores the set of filtered trace event types in set, if successful.

ERRORS

       These functions shall fail if:

       EINVAL The value of the trid argument does not correspond to an active trace stream or the value of the	argument  pointed  to  by  set	is
	      invalid.

       EINTR  The operation was interrupted by a signal.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       None.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       Trace  and  Trace  Event  Filter  Options:  System  Trace  Events , Trace, Trace Log, and Trace Event Filter Options: System Trace Events ,
       posix_trace_eventset_add() , the Base Definitions volume of IEEE Std 1003.1-2001, <trace.h>

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol-
       ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
       Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and  the  original  IEEE
       and  The  Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained
       online at http://www.opengroup.org/unix/online.html .

IEEE
/The Open Group						       2003						 POSIX_TRACE_GET_FILTER(P)